Acceleration of vulcanization of rubber



Patented Nov. 15,1938 2,136,949

OF VULCANIZATION OF RUBBER I Ludwig ()rtlmer, Leverkusen-on-the-Rhine, and

Ewald Zancker,- Cologne-Mulheim-on-the- Rhine, Germany, assignors to I. ,G.. Farbenim dustrie Aktiengesellschait, Frankfort-on-the- ACCELERATION Main, Germany fully described in the annexed examples.

soluble inwater, soluble in the usual organic sol- No Drawing. Original application June 23, 1931,

Serial No. 546,418. Divided and this application July 1, 1932, Serial No. 620,526. In Germany June 30, 1930 r 9 Claims. 18-53) The present invention relates to a process of As suitable compounds of the .general formula 1 vulcanizing rubber and to the vulcanizates ob- 0 K tainable by said process.

Mercaptoarylenthiazoles have already been I 5 suggested for accelerating vulcanization. This 1/ 5 class of substances possesses, however, the disad- 7 coming into consideratlon for the purpose of vantage of an unfavorable critical temperature, our invention, there may be mentioned by way that is to say, the use thereof involves the danger of example: of scorching,v i

1 In accordance with the present inventionnat- Chlomacetone' 10 ural rubber or artificial rubber-like masses ob- Cram-001C113? tainable, for example, by polymerizing butadiene chlommethylethylketone= or another homologue or an analogue of buta- (mam-005235? diene, are vulcanized with the addition of new dlchlomacetone:

vulcanization accelerators, possessing consider- CHCh'Co'Cm? ably more favorable critical temperatures, said dlchlqroacetonei new vulcanization accelerators having the probcHzcl-co-cflzcl; able general formula -Bromoacetoacetic acid ethyl ester:

CH2BI.CO.CH2.COOC2H5; 7-I0dili6 acetoacetic acid methylester: 20

R N (1s( :11C CH2J.CO.CHz.COO.CH3;

. x n-Bromoacetophenonez wherein R stands for a benzene or naphthalene CH2Br.CO.CsH5; nucleus, which may be substituted by monovafl-c o 'fle p e fl e2 lent substituents, for example, by alkyl, alkoxy, CH2Cl.CO.CaH4.NO2; 25

halogen or nitro groups, :1: stands for hydrogen -C OI' -D y p or a -mercaptoarylenethiazole radical being at- CHzCLCQCeHaCHEs; tached with the sulfur atom of the mercapto Dichloroacet-amide: group to the carbon atom of the (EH-group, and CHClaCQNHz;

1; stands for alkyl or aryl, which maybe substi- N-dichloro-acetepiperidide: 30 tuted, or an amino group, which may likewise CHCl2.CO.N=CsHw; be substituted. Dichloro-acet-anilide: V

These new accelerators are obtainable by re- CHCl2.CO.NH.CsH5; acting upon an about molecular quantity of a N-dichloro-acetyl-anthranilic acid ethyl ester:

compound of the general formula: v CHClz.CO.NH.CaH4.COOC2Hs: 35

/0 Dichloroacetyl-dlmethylamide: 1 .c c CHC12.CO.N(CH3)2;

Dichloroacetyl-dibutylamide: wherein Hal stands for a halogen atom, :1: stands Dichloioacet l-dibenzylamide. 40 for hydrogen and y stands for alkyl or aryl, CHCh Co Nwm Cans, which may be substituted or an amino group, As dichlomacetyl phenylilydi,azlde which may likewise be substituted, with about one molecular proportion of a mercaptoarylenethi- CHCh'CQNHNHCSHE a ,As. dichloro-aceto-ortho-nitro-phenylhydrazide: azole or a salt thereof in case 1' represents hy- CHCI 2.CO.NH.NH.CBH4.NO2, drogen in the second general formula, or with Diem r t 1 m lamide, V about two molecular proportions of a a-mercapto- 0 0 ace y p g b NH C H arylenethiazole or a salt thereof in case a: rep- 3 resents halogen in the above second general for- The new accelerators are generally colorless mula, said process of manufacture being more to yellowish colored crystalline substances, inm vents, and are particularly valuable in view of their favorable critical temperatures.

For vulcanization purposes the new vulcanization accelerators are incorporated within the rubber (which term is intended to include natural rubber as well as artificial rubber-like masses, derived for example, from butadiene, isoprene, dimethylbutadiene or another homologue or an analogue of butadiene) in any desired manner, for example, by rolling or kneading. Obviously, a vuloanizlng agent, such as sulfur, agents being capable of splitting ofl sulfur, selenium etc., is likewise added, and, if desired, other ingredients known to favorably influence rubber vulcanization processes or the properties of the vulcanizates, may be admixed to the vulcanization mixture. The latter is then vulcanized in the usual manner by heating it to a temperature suflicient to perform vulcanization, for example, to a temperature between about 100-170 C.

Representative of this new class of accelerators, which possess too low a velocity on hot vulcanization, can be adjusted to give more favorable times of heating by combination with stearic acid toz Example 1 To a solution of 100 grams of ,u-mercaptobenzothiazole' and 24 grams of sodium hydroxide in 200 cos. of methyl alcohol, 55 grams of chloroacetone are dropped while stirring and while cooling with ice. The mixture is then boiled for several hours and, after reaction is finished,

poured on to ice water. After recrystallization from ethyl etherthe reaction product obtained.

has the melting point of 70 C. The reaction performs according to the probable equation:-

C. The reaction proceeds according to the probable equation:--

lONH:

Example 4 In comparison with mercaptobenzothiazole (I), the condensation products from mercaptobenzothiazole (sodium salt) and beta-dichloroacetone (II), as.-dichloroacetone (1H) and dichloroacetamide (IV) were tested as accelerators in the fol- 1 part by weight of accelerator or 0.8 part by weight of accelerator for as.-di-

chloroacetone (III) The following figures were obtained:

A=tensile strength in kg. per sq. cm. B=stretch in percent.

Heating I II III IV 55%; A B A B A B A B atm. mes

0.5 so to 94s 15 1092 a 1m 808 140 869 140 170 m 818 With a mixture of the composition:-

Parts by weight Crepe 100 Zinc mrirln 5 Sulfur I 3 Stearic acid 1.5

and 0.67 part by weight of mercaptobenzothiazole acetonyl ether-[e033 part by weight of diphenylguanidine (V) or 0.33 part by weight of the reaction product of mercaptobenzothiazole (sodium salt) with dichloroacetamide+0.87 part by weight of diphenylguanidine (VI) s s the following figures were obtained:-

Example 2 Heating v VI When substituting in Example 1 the 55 grams 33?,- Mmum A B A B of chloroacetone by a solution of 38 grams of sym.-dlchloroacetone into 50 cos. of acetone and 0 30 1045 on pouring the mixture into water after a short 31o us m 814 "ii" 556" time's boiling, the reaction product obtained after 3-3 23 a g: gag recrystallization from benzlne has the melting point of 129 C. This reaction proceeds accord- This is a division of our co-pending application ing to the probable equation: Serial No. 546,418, filed June 23, 1931.

' N N N N r o.s.N-+c1 cm.c 0.cH,.cl+Nn.s.c 2Na0l c.s.cm.co.cm.s.c s s I s s I Example 3 100 grams of -mercaptobenzothiazole are boiled with 24 grams of sodium hydroxide in 200 cos. of methyl alcohol and 38.4 grams of dichloroaeetamide for 5 hours. After that the reaction We claim:-

1. The process which comprises incorporating within rubber a vulcanizing agent and a compound of the formula: I

and vulcanising the mixture.

2. The process which comprises incorporating within rubber a vulcanizing agent, a basic accelerator and a compound oi the formula:-

and vulcanizing the mixture.

3. The process which. comprises incorporating within rubber a vulcanizing agent, diphenylguanidine and-a compound of the formula:-

and vulcanizing the mixture. 4. The vulcanizates obtainable in accordance, with the process claimed in claim 1.

5. The vulcanizates obtainable in accordance with the process claimed in claim 2.

6. The vulcanizates obtainable in accordancewith the process claimed in claim 3.

7. A process of accelerating the vulcanization oi rubber that comprises vulcanizing in the'presence of carbamyl methyl di(ben'zothiazyl l-sulphide);

8. A process of accelerating the vulcanization;

of rubber that comprises vulcanizing inthe presence of a carbamyl methyl benzothiazyl l-sulphide.

9. A process 'of accelerating the vulcanization of rubber that comprises vulcanizing in the presence ofa carbamyl methyl benzothiazyl I-sulphide and a basic organic nitrogen-containing accelerator.

LUDWIG OR'I'HNER, EWALD ZAUCKER... 

